code: def setUp(self):
      if mpl is None or plt is None:
          raise unittest.SkipTest(
              "matplotlib not found, skipping tests"
          )
  
imports: import os
  import unittest
  from igraph import Graph, plot, VertexClustering, Layout
  from ...utils import overridden_configuration
label_desc: Use image node_id 1 for calling the ClusteringTestRunner obj's underlying member method code with example usage: obj.setUp() without return types